GCC4.6: Squash warning in cfi_flash.c

cfi_flash.c: In function 'flash_protect_default':
cfi_flash.c:2152: warning: format '%08x' expects type 'unsigned int', but
argument 2 has type 'ulong'
cfi_flash.c:2152: warning: format '%08x' expects type 'unsigned int', but
argument 3 has type 'long unsigned int'

Signed-off-by: Marek Vasut <marek.vasut@gmail.com>
Cc: Wolfgang Denk <wd@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Scott Wood <scottwood@freescale.com>